Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
A lower limit on energy spent in a computing operation may be determined by a requirement that the generated electrical signal be larger than the noise. There are typically two major sources of noise in electrical system, thermal noise and random telegraph signal (RTS) or 1/f noise. The signal to noise ratio in electrical systems is proportional to the excess of the signal over the noise, which is typically inversely proportional to the bit error rate (BER).
Energy efficient computing circuits may use low power supply voltages and low signal voltage levels while still maintaining a desirable BER. Power dissipation, or energy consumption, in logic circuits may depend upon the square of the magnitude of the signal level (e.g., voltage) in comparison to the square of the magnitude of the thermal noise, and linearly upon the frequency of operation of the logic circuits. Various techniques available to reduce thermal noise, to increase the signal to noise ratio, may include lower bandwidths of operation, lower speed computing circuit operations, or lower temperatures of operation.